Mount for electron-emission devices and method of making



Feb. 21, 1928.

D. D. DEMAREST MOUNT FOR ELECTRON EMISSION DEVICES AND METHOD OF MAKING Filed (3'31;' 27, 1922 INVENTO R DAN/7. a. DEMAREST M ATTORNEY Patented Feb. 21, 1928.

UNITED STATES PATENT OFFICE.

DANIEL DOUGLAS DEMAREST, OF MONTCLAIR, NEW JERSEY, ASSIGNOB TO WESTING- HOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

MOUNT FOR ELECTRON -EMISSION DEVICES AND METHOD OF MAKING.

Application filed October 27, 1922.

This invention relates to the manufacture of electron-emission devices such as are used in connection with radio apparatus and the like.

An object of the invention is to provide an electron-emission device having the elements and supporting structure thereof of such form as to facilitate the assembly and union of the elements.

Another object is to provide an electroncmission device in which the grid and plate are of trough shape.

A further object is to provide a mount for electron-emission devices of such construction as to reduce microphonic effects.

Other objects and advantages will be apparent from the following description.

The invention is particularly adapted for use in connection with electron-en'iission devices as employed with radio equipment. Such devices usually comprise a bulb in which is sealed a mount after which the bulb is evacuated by any suitable means. Devices of theabove character have become generally known in the art as radiotrons.

The mount which constitutes the internal structure of a radiotron generally comprises a cathode or filament positioned within a grid which in turn is surrounded by an anode or plate. These three elements are usually held in given relative positions by supports and by relatively rigid leading-in Wires which are embedded in a press; namely, the compressed portion of one of the component parts of the mount termed the flare-tube.

it is of great importance in the manufac- Lure of radiotron mounts to properly posis tion the elements inthe desired relation, particularly the filament and grid. For efficient service and practical working conditions, it is essential to properly dispose the filament and grid so that a symmetric space will be maintained between these elements when they are mounted. Grids as heretofore constructed, have been formed of either cylin- (ll'lCul or substantially oval transverse cross section and it has been the practice to posi tion the filament within the encompassing sides of the grid.

Considerable difliculty, however, was encountered since it was heretofore necessary for an, operator to exercise considerable skill and be subject to more or less eye-strain to properly insert and align the filament with respect to a tubular grid. It very often Serial No. 597,250.

happened that as it was not possible for the operator to properly inspect the filament throughout its whole length, an unsymmetrical spaced relation existed between the filament and grid when these elements were mounted. This condition resulted in a deterioration of the filament and shortened the life of the device.

The present invention rovides a grid of trough or U-shape and a lament may readily be moved sideways into proper proximity to the grid-walls without the exercise of any exceptional skill on the part of an operator. Furthermore, the rapidity with which a filament may be disposed Within the grid is greatly imcreased and the tedious and time consuming operation of threading a filament through a grid, of the tubular type, is eliminated. Great advantage in production is thereby derived since the output of an operator is greatly increased.

In addition to the facility with which the filament may be assembled I also provide for resiliently supporting the filament which may consist of a single wire secured at its ends to relatively flexible support members. The supports are so constructed as to exert a tensional stress upon a mounted filament and thereby maintain the filament with its axial line in the desired position. The resilient property of the supports however, provides for the dissipation of shocks and jars incident to the handling of the tube during transportation and use.

It will therefore be understood that my invention not only provides for the convenient and rapid adjustment of a filament within a grid and for the quick assembly of a plate about the grid, but also provides a durable and practical device.

" I have also found, in practice, that when operating with a trough-shaped grid or with a grid and plate, both of trough-shape, a considerable reduction in mierophonic effects results.

The invention will be more fully understood by reference to the accompanying drawings, in which,

Fig. 1 is a side elevational view of a radio tron having a mount embodying my invention;

Fig. 2 is an end mount shown in Fig. 1;

Fig. 3 is a top view of the mount shown in Fig. 1;

elevational view of the Fig. 4 is a side view in elevation of a mount embodying the present invention but showing a modified arrangement;

Fig. 5 is an end view of the mount shown in Fig. 4;

Fig. 6 is a fragmentary perspective view showing the relative positions of some of the elements of the mount; and,

Fig. 7 is a top view of the mount but shows another form of grid and a cross or tie-piece for tying one element to another.

As illustrated, the invention may comprlse a mount 8 including a flare tube 9 wh1ch 1s provided with the usual flare press 10 in which is embedded support wires 11 and 12 to which a plate 13 is secured by welding or otherwise attaching the wires to ears 14:. The support wire 12 may have a lead-1n w re or conductor 15 connected thereto. Disposed Within the plate, is a grid 16 welded or otherwise secured to relatively rigid sup-- port wires 17 and 18 which are also embedded in the press 10. The support wire 17 may have a leading-in wire or conductor 19 connected thereto.

The grid 16, as more clearly shown in Fi 3, is of substantially trough-shape or U- hape in transverse cross section and may comprise a plurality of sections of relat vely fine wire 20 secured to two comparatively rigid members 21 disposed in parallelrelation. These rigid members are so positioned as to constitute what may be termed edges of the longitudinal opening of the trough.

A filament 22 which preferably consists of a single wire may readily be positioned in the trough and may be supported at its upper end by a resilient support member 23 and at its lower end by another similar member 24. Both these members are embedded in the press 1.0 and leading-in wires 25 and 26 maybe connected with the upper and lower supportingmembers respectively.

It will be noted that the plate or anode shown in the foregoing described figures is of the tubular form and completely surrounds the grid and filament. However, if desired, the plate may also be of troughshape. An example of a mount employing a trough-shaped grid and a trough-shaped plate is shown in Figs. 4, 5 and 6 in which a plate 27 is of U-shape in transverse cross section and is disposed with its open side opposite the press 1.0 and having therein the grid 16 which is similarly disposed. The filament having previously been positioned on the mount, the other elements are secured in proper relation thereto.

As shown, the filament is secured to support members 28 and 29. These members are embedded in the press 10 in comparatively close relation and diverge therefrom in opposite directions. The filament 22 may be secured to the supports 28 and 29 by welding or otherwise.

,most entirely surround the filament.

sired, the opening may be entirely closed by It will be appreciated that in practice, a filament may be secured to the support members and a grid may be conveniently and quickly positioned over the filament and maintained in place by welding or otherwise securing to a support member 31 embedded in the press 10. It has been found that only one support member is necessary to properly support the grid although two or more such members may be employed if desirable. The plate 27 is then placed over the grid 16 and is secured to support members 32 and 33 which are also secured in the press 10. v

The diverging support members which carry the several elements alford considerable advantage since they provide resilient lever arms which absorb and dissipate vibration or forces due to sudden impacts, thus providing a more rugged mounting for the elements.

In the manufacture of radiotrons, it necessary to treat out certain of the elements particularly the plate, to remove various deleterious gases therefrom. This is usually accomplished electrically, by induction and in order to provide a closed circuit and more readily heat the plate of trough-shape, a-

conductive bridging member 34, as shown in Fig. 6, may be provided. A conductive member may be provided at both ends of the trougli, if desirable, or a section of the plate may be bent across the opening to provide the necessary conductive medium to permit the passage of current whereby the plate may be more readily heated.

As illustrated in Fig. 7, a grid 36 is shown as almostsurrounding the filament 22. This grid may be originally formed of substan tially thesame cross sectional configuration as the grid 16 but the support wires 17 and 18 may be positioned in the press so that their exposed ends are in close proximity. Thus after a filament has been properly positioned, the grid may be passed lhereover and the rigid members 21 of the grid may be moved and secured to the support wires 17 and 18 thus reducing the width of the opening through which the filament has passed and thereby causing the grid to al- If depripging the members 21 of the grid in con- It will be appreciated that by this method of mounting the elements, ample space is provided for the passage of the filament and that this passage may be readily closed as described.

Another feature shown in Fig. 7 consists the bead :hardens.

support 23. These two rods are secured together by means of a non-conductive coupler preferably in the form of a glass bead 41. Thus when the tie-piece is properly secured to the plate support and the filament support, the bead may be heated until plastic and the said supports may be adjusted to the desired position and thus maintained when This tie-piece or cross member acts to impart stability to the fabrication which constitutes the structure for supporting the various elements.

It will be evident that a radiotron constructed in accordance with my invention will provide a device which may be manufactured in large quantities with a minimum amount of labor and skill. Furthermore, a filament may be held under light tension and then clamped to the support members which maintain the filament in the desired rectilinear form. Since the filament support members may be spaced a uniform distance apart, a filament of a uniform length may be obtained for each device which is an advantage in the production of tubes having uniformity of operation.

Although I have shown and described one embodiment of my invention, it is obvious that various changes may be made therein without departing from the spirit and scope of the appended claims.

What is claimed is:

1. An electron-emission device comprising a trough shaped plate, a grid within said plate comprising a plurality of U-shaped members secured at their ends to two relatively heavy cross-members, said heavy members uniting the ends of the U-shaped members and a filament positioned in said grid.'

2. An electron-emission device comprising atrough shaped plate, a trough shaped grid within said plate comprising a plurality of U-shaped members secured at their ends to two relatively heavy cross-members positioned to constitute the edges of the trough shaped grid and a filament positioned within said grid and substantially in concentric relation to the rounded portion thereof.

3. An electron-emission device comprising a trough shaped plate, a grid within said plate comprised of a plurality of U-shaped members secured at their ends to two relatively heavy cross-members, a filament positioned in said grid and means for resiliently supporting said filament in substantially concentric relation to the rounded portion of said grid.

4. An electron-emission device comprising a bulb, a stem press within said bulb, a trough shaped grid secured to said press and positioned with the open side thereof opposite said press, a filament, means associated with said press for supporting said filament within said grid, a trough shaped plate, means associated with said press for supporting said plate in a given relation to said grid and a conductive member bridging the trough of said plate.

5. The method of mounting a plurality of elements including a filament and grid in an electron-emission device which comprises providing the grid with a relatively large opening for the admittance of the filament and in reducing the width of said opening subsequent to the disposition of said filament within said grid.

6. The method of mounting a plurality of elements including a filament and grid in an electron-emission device which comprises providing the grid with a relatively large longitudinal opening for the admittance of a filament, closing said opening and securing said grid in a given relation to said filament.

7. The method of mounting a plurality of elements including a filament and a troughshap-ed grid in an electron-emission device which comprises securing a filament to support members, disposing the trough shaped grid about said filament and in changing the relative positions of the edges of said trough after the disposition of a filament therein.

8. The method of makin an electron-emission device having a trough shaped grid and an electrode support having a fusible coupler, comprising attaching an electrode to said support, positioning said grid about said electrode, closing the longitudinal opening of said trough, softening said coupler to permit an adjustmentof said electrode and permitting said coupler to harden to secure said electrode in its adjusted position.

9. The method of making an electron-emission device having trough-shaped plate and grid and a filament support having a fusible coupler, comprising securing a filament to said support, moving the grid to cause the filament to pass through the longitudinal opening of the trough and disposing the plate about the grid by moving the plate so that the grid passes through the longitudinal opening of the trough-shaped plate and in softening the cou ler to adjust theposition ofthe filament wit respect to the grid.

10. The method of making an electronemission device having a trough-shaped element and an electrode support having a fusible coupler, comprising securing a filament to said support, moving the trough-shaped element to cause the filament to be positioned in the trough of said element, and closing the longitudinal opening of said element.

In testimony whereof, I have hereunto subscribed my name this twenty-six day of O0- tober, 1922.

DANIEL DOUGLAS DEMAREST. 

